1. Field of the Invention
The present invention relates to circuit breakers, more particularly, relates to a contact module for circuit breaker with an asymmetric structure.
2. The Related Art
It is well known that a circuit breaker with dual breakpoint has a current breaking capacity which is much higher than a circuit breaker with single breakpoint. The circuit breaker with dual breakpoint utilizes modularized structure which results in convenient assembly and good insulation ability. However, dual breakpoint structure requires that each level of the circuit breaker comprise two contact modules. The contact modules shall have high strength since the circuit breaker will bear large breaking current and the contact modules will bear strong gas shock waves. A high strength requires that a housing of the contact module shall have sufficient thickness, so a phase spacing of the circuit break cannot be reduced. For circuit breakers with large current breaking capacities such as 100 A, 125 A or 160 A, a width dimension of the circuit breakers will be very large. However, miniaturization is a demand and trend for circuit breakers. It is obvious that there is a contradiction between the current breaking capacity and the dimension of a circuit breaker.
For example, an existing four-level circuit breaker with a current breaking capacity of 160 A has a width dimension of 120 mm and a spacing of 30 mm. Though the circuit breaker may bear a large current, the dimension of the circuit breaker is too large and will obviously constrain the application and installation of the circuit breaker.